Image sharpness in lenticular films



Oct. 14, 1958 J. A. SCHWAN ET AL 2,856,282

IMAGE SHARPNESS IN LENTICULAR FILMS Filed June 8, 1956 S/L VE/P HAL/0E EMULSION I con/rammva ETHYLENE 0x/0 POLYMER JUDITH A. SCHWA/V ROBERT E. STAUFFER VENTORS A TTOR/VEYS nited States Patent IMAGE SHARPNESS IN LENTICULAR FILMS Judith A. Schwan and Robert E. Stauffer, Rochester,

N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporaiton of New Jersey Application June 8, 1956, Serial No. 590,173

5 Claims. on. 9626) since this improves image sharpness and therefore improves color saturation and brightness. However, an ammonia developer is objectionable not only because of its odor but because the ammonia evaporates and makes control of the process difiicult.

It is, therefore, an objectof thepresent invention .to provide a lenticular film capable of producing images of improved sharpness. A further object is to provide a lenticular film which produces images of improved color saturation and brightness. A still further object is to provide a lenticular film which need not be developed in an ammonia developer. Other objects will appear from the following description of our invention.

These objects are accomplished by incorporating in the lenticular film emulsion an ethylene oxide polymer of the classof polyethylene glycols or condensation products of ethylene oxide with organic compounds having an active hydrogen atom, the ethylene oxide polymer having a. molecular weight of at least 300.

The accompanying drawing is a sectional view of a film constructed according to our invention.

The structure of lenticular films is well known in the art. A film base, usually of cellulose ester, has embossings or lenticules on one side and a gelatino-silver halide emulsion on the opposite side. This film is used in a camera with the lenticulated side toward the lens. The object being photographed is imaged upon the film by the camera lens and a banded color filter axially lo cated in front of the lens is imaged by each lenticule onto the emulsion area lying directly behind it. The color separations produced by the action of the filter are recorded as separate elements behind each lenticule. If color separation images, such as those produced in a television system are to be recorded, stops and apertures are used in place of the banded filter. Each separation is recorded through its appropriate stop to record the images separately in the emulsion layer behind each lenticule.

In order to obtain the requisite sharpness in the images produced in such film, it is customary to develop the emulsion after exposure in an ammonia developer, for example, a developer of the following composition:

Water to 1 liter.

"ice

When developed in a developer of this or similar com position, the film produces images of satisfactory definition and sharpness. However, as stated above, the use of an ammonia developer is objectionable, but if an ordinary developer free of ammonia is used, there is an appreciable loss in sharpness of the resulting images.

We have found that this loss in sharpness may .be

overcome and images of satisfactory sharpness and color saturation may be produced by incorporating in the silver.

The ethylene oxide polymer used in the emulsion maybe of various types. The preparation of these polymers is described in Ellis, The Chemistry of Synthetic Resins (11935), pages 990-994. These compounds are also referred to as polyethylene glycols and their use in silver halide emulsions is described in U. S. Patents 2,423,549 and 2,441,389. The ethylene oxide derivatives may be prepared by condensing an organic compound containing an active hydrogen atom with an ethylene oxide polymer, or by condensing the active hydrogen compound with the ethylene oxide during the polymerization of the latter material.

Various derivatives of ethylene oxides may also be used in the emulsion, e. g., condensation products of ethylene oxide with organic compounds containing an active hydrogen atom. Examples of active hydrogen organic compounds, 1. e., compounds in which a hydrogen atom may be replaced by reaction of the compound with metallic sodium methyl magnesium iodide, etc., include alcohols, amines, mercaptan acids, amides, hydrocarbons such as acetylene, and compounds having the active hydrogen in a methylene group such as dibenzoylmethane. More specifically, we may employ condensation products of ethylene oxide with glycols such as those having from 8 to 18 carbon atoms as described in U. S. Patent 2,240,472 and British Patent 443,559, as well as condensation products of ethylene oxide with aliphatic alcohols, condensation products of ethylene oxide with aliphatic acids, e. g., lauric acid and glycine, condensation products of ethylene oxide with aliphatic amines or amides, e. g., glycine and lauryl amide, and condensation products of ethylene oxide with phenols, e. g., phenol.

The preparation of these condensation products is described in U. S. Patent 1,970,578. Condensation prod-- nets of ethylene oxide with hexitol ring dehydration prod ucts as described in U. S. Patent 2,400,532 may also be employed.

In each case, the polyethylene oxide or derivative of ethylene oxide should have a molecular weight of at least 300. Condensation products of ethylene oxide with long chain alcohols, acids, amines or amides should have a molecular weight of about 700. In general, the best results are obtained with the condensation products of ethylene oxide with long chain compounds having a chain length of 12 or more carbon atoms and with ethylene oxide polymers having a molecular weight of 1500 to 4000 or more. A suitable amount of the ethylene oxide polymer is 1 gram per gram mole ofsilver halide in the emulsion.

An emulsion suitable for use according to our invention is a silver bromoiodide emulsion containing 3.4 mole percent iodide and 1 gram of the condensation product of 1 mole of oleyl alcohol with approximately 25 moles of ethylene oxide (polyethyleneglycol oleyl ether) per mole of silver halide. After coating this emulsion on the lenticulated support, the following reversal process may be used to produce an image according to our invention.

After exposure of the emulsion through the support len- 3 ticulations, the film is developed for to minutes in the following solution:

Grams Hydroquin ne 9 Sodium sulfite (anhydrous) Sodium carbonate, monohydrate 30 Potassium bromide 5 Water to 1 liter.

After a three minute wash, the film is bleaced for 3 minutes in a solution of 5 grams of potassium dichromate and 10 cc. of concentrated sulfuric acid in 1 liter of water, washed 3 minutes, cleared 3 minutes in sodium bisulfite solution, re-exposed and developed in the following developer for 4 minutes:

Grams N-rnethyl-p-aminophenol sulfate 0.3 Sodium sulfite (desiccated) 38.0 Hydroquinone 6.0 Sodium carbonate (monohydrate) 22.5 Potassium bromide 0.9 Citric acid 0.7 Potassium metabisulfite 1.4

Water to 1 liter.

After a 30 second treatment in 3% acetic acid solution to stop development, the film is then fixed for 5 minutes in a standard fixing bath, washed in water and dried.

Sharpness can also be improved by incorporating various substituted amines in the first developer in place of sodium carbonate. This modification of the first developer produces colors nearly as saturated as those produced with the usual emulsion processed in the ammonia developer. Suitable substituted amines are cyclohexylaminopropanol, monoethaminolamine, ethylenediamine,

isopropylamine, but ylamine and furfurylamine. With this developer, either the usual emulsion or an emulsion containing polyethyleneglycol oleyl ether may be employed. The following solution illustrates the first developer, which is preferred to the hydroquinone first developer in the process above:

Grams N-methyLp-aminophenol sulfate 6 Hydroquinone 4 Sodium sulfite (anhydrous) 24 Potassium bromide 10 Cyclohexylaminopropanol 10 Water to 1 liter.

Emulsion Control with Poly- Emulsion ethylene glycol oleyl ether Hydroquinone, first developer 5 8 M'Q .Oyclohexylaminopropanol, first developer 7 10 ill 4; These results indicate that the color saturation was improved in each case when the polyethylene glycol was added to the emulsion.

When processing simply to a negative, the developer is the same as the first developer used in reversal processes. For television purposes, either a negative or a positive record may be used.

In the accompanying drawing which illustrates one modification of our invention, 10 illustrates the support having lenticules 11 on one side thereof and on the other side thereof emulsion layer 12 containing an ethylene oxide polymer.

It will be understood that the examples included herein are illustrative only and that our invention is to be taken as limited only by the scope of the appended claims.

What we claim is:

1. A lenticular photographic film capable of producing photographic images of improved image sharpness, comprising a lenticulated photographic film base having on the side opposite the lenticules, a silver halide emulsion having incorporated therein an ethylene oxide polymer selected from the class consisting of (1) polyethylene glycols and (2) condensation products of ethylene oxide with organic compounds having an active hydrogen atom, said ethylene oxide polymer having a molecular weight of at least 300.

2. A lenticular photographic film capable of producing photographic images of improved image sharpness, comprising a lenticulated photographic film base having on the side opposite to the lenticules, a silver halide emulsion having incorporated therein a condensation product of ethylene oxide with an aliphatic alcohol, said condensation product having a molecular weight of at least '300.

3. A lenticular photographic film capable of producing photographic images of improved image sharpness, comprising a lenticulated photographic film base having on the side opposite to the lenticules, a silver halide emulsion having incorporated therein polyethylene glycol oleyl ether.

4. The method of improving image sharpness, color saturation and brightness of an image in alenticular film emulsion, which comprises incorporating in a silver halide emulsion coated on a lenticular support on the side opposite to the lenticules, an ethylene oxide polymer selected from the class consisting of (1) polyethylene glycols and (2) condensation products of ethylene oxide with organic compounds having an active hydrogen atom, said ethylene oxide polymer having a molecular weight of at least 300, exposing said emulsion to an object or.

image through said lenticules, and developing said emulsion in a silver halide developing solution free of ammonia.

5. The method of claim 4, in which the ethylene oxide polymer is polyethylene glycol oleyl ether.

References Cited in the file of this patent UNITED STATES PATENTS 2,351,019 De Lassus Saint Genies June 13, 1944 2,423,549 Blake et al July 8, 1947 2,441,389 Blake May 11, 1948 2,543,073 Stevens Feb. 27, 1951 2,588,615 Capstaff Mar. 11, 1952 

4. THE METHOD OF IMPROVING IMAGE SHARPNESS, COLOR SATURATION AND BRIGHTNESS OF AN IMAGE IN A LENTICULAR FILM EMULSION, WHICH COMPRISES INCORPORATING IN A SILVER HALIDE EMULSION COATED ON A LENTICULAR SUPORT ON THE SIDE OPPOSITE TO THE LENTICULES, AN ETHYLENE OXIDE POLYMER SELECTED FROM THE CLASS CONSISTING OF (1) POLYTHYLENE GLYCOLS AND (2) CONDENSATION PRODUCTS OF ETHYLENE OXIDE WITH ORGANIC COMPOUNDS HAVING AN ACTIVE HYDROGEN ATOM, SAID ETHYLENE OXIDE POLYMER HAVING A MOLECULAR WEIGHT OF AT LEAST 300, EXPOSING SAID EMULSION TO AN OBJECT OR IMAGE THROUGH SAID LENTICULES, AND DEVELOPING SAID EMULSION IN A SILVER HALIDE DEVELOPING SOLUTION FREE OF AMMONIA. 